1. Field of the Invention
This invention relates to a thoracostomy tube enabling dislodgment of blood clots which may form within the tube during drainage without the need to expose any portion of the tube which has been inserted into the thorax area of the body to the outside atmosphere, thereby avoiding the introduction of bacteria or other infectious agents into the body after removing the clot and maintaining sterile conditions.
Intrathoracic bleeding occurs with any form of chest injury that disrupts the tissues. In most instances of penetrating or non-penetrating trauma the blood is shed into the pleural cavity, often with some degree of pneumothorax.
From accumulated military and civilian experience, it can be estimated that slightly more than 10 percent of patients with traumatic hemothorax will require thoracostomy for control of bleeding or determination of the extent of injury. A progressive hemothorax or continued bleeding at the rate of more than 100 ml/hour beyond a few hours after placement of an intercostal catheter suggests bleeding from an intercostal artery, the internal thoracic artery, or a source that will require operative control.
Movement of the diaphragm and thoracic structures causes partial defibrination of blood that is shed into the pleural cavity, and clotting is usually incomplete. Sufficient coagulation does occur to interfere with efficient drainage of the pleural blood through intercostal catheters, and the latter often become plugged with a blood clot. Unless the pleural space is drained adequately, the transudation of fluid into the space can produce significant compression of the lung and a shift of the mediastinum toward the opposite hemothorax.
When the hemothorax exceeds an amount that fills the costophrenic sulcus, or when there is an associated pneumothorax, one or more large catheters should be placed in the pleural cavity. Drainage alone may be sufficient, but low suction applied to the catheters is often helpful when combined with active efforts at stripping the tubes of blood clots.
With a major hemothorax the success of tube drainage is often frustrated by extensive clotting which obstructs the tubes. A nonfunctioning chest tube represents a liability to the patient because of discomfort and the risk of carrying infection from the skin wound into the pleural area.
Especially with penetrating trauma, a hemothorax that fails to drain adequately through intercostal catheters may develop into empyema. An additional hazard is the organization of residual clot to form a fibrothorax. Although the incidence of these complications is not high, the consequences are severe, and it is wiser to proceed with thoracostomy and evacuation of the hemothorax before an extensive decortication becomes necessary.
In addition to traumatic causes of hemothorax, iatrogenic hemothoraces are induced during cardiac and coronary bypass surgery, and virtually always require thorocostomy tube drainage. Such surgery provides a major area for the application of the thrombus-mobilizing chest tube.
Further information about traumatic hemothorax may be found on page 630 of Principles of Surgery, 4th edition, by S.I. Schwartz, published in New York by McGraw-Hill in 1984.
2. Description of Related Prior Art
In a conventional thoracostomy tube which lacks any means for actively stripping a blood clot from the tube, the tube must be removed from the thoracic area before dislodging the blood clot from the tube. When the tube is removed even partially it is exposed to bacteria or other contaminants, thereby increasing the risk of infection when the tube is reinserted.
A number of devices are known in the prior art for stripping catheters of blood clots. U.S. Pat. No. 3,863,641 issued Feb. 4, 1975 to Loan Pop D. Popa discloses one such device for a catheter comprising a transparent elastic tube 1 having a plurality of orifices a, an inflatable balloonet 4 which acts as a piston, a mandrel 3 for moving balloonet 4, and a rigid tube 10 used to introduce liquid flushing material such as a heparin solution into tube 1. In the single figure, when a blood clot has formed, balloonet 4 is moved vertically in tube 1 to a position above orifices a by means of mandrel A, pushing the blood clot ahead of balloonet 4 while blocking access to orifices a by the liquid flushing material introduced into tube 1 through tube 10. Since at least a portion of mandrel 3 is moved outside of tube 1, mandrel 3 is exposed to a variety of contaminants which are introduced into the body when the balloonet 4 is returned to its initial position at the distal end of tube 1, thereby increasing the risk of infection. U.S. Pat. No. 4,228,802 issued Oct. 21, 1980 to William A. Trott discloses a self-inflating and self-cleaning catheter assembly which incorporates a selectively insertable auger assembly for removing blood clots. Because the auger assembly is exposed to the outside atmosphere before being introduced into the catheter, the risk of infection is increased. U.S. Pat. No. 4,762,130 issued Aug. 9, 1988 to Thomas J. Fogarty, Thomas B. Kinney and James C. Finn discloses a catheter with a corkscrew-like balloon. As in the Popa disclosure, the balloon in Fogarty et al. is used like a plunger, moving in and out of blood vessels to remove blood clots after the blood clots have been speared by the auger shape. Again, because at least portions of the controlling structure are exposed to the outside atmosphere, the chances of infection when the tube 10 is reintroduced into the body is increased. U.S. Pat. No. 4,954,129 issued Sep. 4, 1990 to David Giuliani and Gerald G. Vurek discloses a catheter arrangement which relies on the use of liquid flushing materials only to remove blood clots and other materials.